Design of a high-sensitivity MTM-based multi-band micro-biosensor for early-stage non-melanoma skin cancer diagnosis in the terahertz region

Non-melanoma skin cancer (NMSC) ranks among the most prevalent cancer types, primarily affecting the outer layer of the skin. Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are the two primary categories of NMSC. While treatable, the efficacy of treatment largely depends on accurate diagnostics. Several methods exist for early-stage NMSC detection, including clinical examination (typically visual inspection) and skin biopsy, though the latter is invasive. Microwave imaging (MWI) has garnered significant attention in recent years as a non-invasive diagnostic technique for various cancers. MWI exploits differences in dielectric properties between healthy and malignant tissues to discriminate and categorize tumors. A subset of MWI, terahertz (THz) biosensors, particularly those operating in the low THz range (up to 10 THz), show promise for analyzing biomarkers present in body fluids. This article proposes a novel THz biosensor structure for detecting NMSC, operating within the range of 0 to 5 THz. The sensor design incorporates meticulously engineered metamaterial layers implemented in microstrip technology to precisely control absorption properties. This control is crucial for distinguishing between healthy and NMSC-affected skin. Comprehensive numerical studies validate the suitability of the proposed sensor for early NMSC detection. Specific case studies and numerical analyses of the absorption profile further illustrate the effectiveness of the device.